\[f(x) = x^{2} - 2x - 3 \Longrightarrow ветви\ \]
\[вверх.\ \ \]
\[x_{0} = \frac{2}{2} = 1,\ \ \]
\[y_{0} = 1 - 2 - 3 = - 4 \Longrightarrow (1;\ - 4).\]
\[E(f) = \lbrack - 4;\ + \infty).\]